1. Field of the Invention
This invention relates to a mechanism for locking the shutter of a floppy disc (hereinafter referred as "FD") when it is in the opened state in a floppy disc drive (hereinafter referred as "FDD").
2. Description of the Related Art
Recently, a FDD has been remarkably improved in terms of size and weight so that its is widely used as an essential component incorporated into office automation appliances. While having proven sophistication as a handy and portable component, it is required to be resilient to heavy usage.
FIGS. 5 and 6 are plan and side views respectively showing essential parts of a conventional FDD. In FIG. 6, a slide plate 20 is mounted on a frame 10 having a groove 11. in the inserting direction of the FD. The slide plate 20 having a diagonal groove 21 acts to guide the pin implanted on the carrier 30 cooperating with the groove 11 of the frame 10 in order to move the FD 40 from an unloaded state shown by solid lines to a loaded state shown by two-dot chain lines. A normally used FD 40 includes a not shown magnetic disc contained within a cartridge 41 having an opening 46 at both sides thereof. The shutter 42 is always biased by a not shown spring in the direction from the left corner 44 to the right corner 43 of the FD 40. In the unloaded state, the shutter 42 covers the head contact portion 47 to protect the magnetic disc by not superimposing the window 45 on the opening 46.
When the FD 40 is inserted into the carrier 30 and reaches a position near the loaded position, the distal end 51 of the shutter opening lever 50 axially and rotatably supported by a pivot implanted on the frame 10 comes into contact with the right corner 43 of the shutter 42. Further insertion of the FD 40 against the bias force of the spring 13 moves the shutter 42 toward the left corner 44 until arriving at the loaded position. In this state, the window 45 and the opening 46 lie on top of one another to expose the head contact portion 47 of the FD 40 in order to enable the data recording/reproducing operation by a not shown head which contacts with both sides of the magnetic disc.
In the loaded state, the shutter 42 is biased toward the right corner 43 by the not shown spring incorporated in the cartridge 41 to contact with the distal end 51 of the shutter opening lever 50. The distal end 51, composed of a cylindrical surface having a small radius, contacts with the cartridge 41 and the corner 43, and is biased only by the above-mentioned incorporated spring and the spring 13 of the shutter opening lever 50. Therefore, when any external impact is applied on the FD 40, the distal end 51 will easily separate from the right corner 43 to close the shutter 42 and would damage the magnetic head by the window 45 of the shutter 42 moving to the closed position.